TROLLEY-GEARED 2749470 - Caterpillar

The supply voltage is routed to terminal 1 of each sensor connector. The sensor return is routed to terminal 2 of each sensor connector. The sensor signal is routed to terminal 3 of each sensor connector. The Electronic Control Module (ECM) provides short circuit protection for the internal power supply. A short circuit to the battery will not damage the internal power supply.Diagnostics on the Cat® Electronic Technician (ET)Wiggle Test - The Wiggle Test allows you to monitor the status of the signals from the sensors.For additional information regarding the Wiggle Test, refer to the documentation that accompanies the Cat ET software.
Illustration 1 g03707285
Primary ECM
Illustration 2 g03707284
Secondary ECM
Illustration 3 g03740067
Selective Catalyst Reduction (SCR) controller
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Determine if a code is active or logged.
Codes
Result: A -3 code is active.
Proceed to Test Step 2.
Result: A -4 code is active.
Proceed to Test Step 3.
2. Create a Short at the Sensor Connector
A. Turn the keyswitch to the OFF position.
B. Disconnect the sensor with the active -3 code.
C. Install the jumper wire between the following terminals at the sensor connector:
- Terminal 3 (signal) and Terminal 2 (sensor return)
D. Connect Cat ET.
E. Use Cat ET to monitor the following:
- -4 code
F. Turn the keyswitch to the OFF position.
Create a Short
Result: A -4 code did not become active.
Proceed to Test Step 4.
Result: A -4 code became active.
Repair: The wiring harness is OK. Replace the sensor.
Verify that the repair eliminated the problem.
3. Create an Open at the Sensor Connector
A. Turn the keyswitch to the OFF position.
B. Disconnect the sensor with the active -4 code.
C. Connect Cat ET.
D. Use Cat ET to monitor the following:
- -3 code
E. Turn the keyswitch to the OFF position.
Create an Open
Result: A -3 code did not become active.
Proceed to Test Step 4.
Result: A -3 code became active.
Repair: The wiring harness is OK. Replace the sensor.
Verify that the repair eliminated the problem.
4. Check the 5 VDC Supply Voltage at the Sensor Connector
A. Turn the keyswitch to the ON position.
B. Measure the voltage at the sensor connector between the following pins:
- Pin 1 and Pin 2
C. Reconnect the sensor.
5.0 0.2 VDC
Result: The supply voltage is approximately 5.0 0.2 VDC.
Proceed to Test Step 5.
Result: The supply voltage is not approximately 5.0 0.2 VDC.
Repair:There is a short in the wiring harness to the battery. Repair or replace the wiring harness.
If the problem is not resolved, proceed to Test Step 5.
5. Perform the Wiggle Test
Carefully following this procedure is the best way to identify the root cause of an intermittent problem.
A. Connect Cat ET.
B. Use CAT ET to perform the following test:
- "Wiggle Test"
C. Slowly wiggle the wiring and the connectors between the P2 connector and the sensor. Pay particular attention to the wiring near each connector. Be sure to wiggle all the wiring.
As you wiggle the wiring look for these problems:
- Loose connectors or damaged connectors
- Moisture on the connectors or the wiring
- Damaged that is caused by excessive